1. Field of the Invention
The present invention relates to a radiation image capturing system having a radiation conversion panel for detecting a radiation that has passed through a subject and converting the detected radiation into radiation image information.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which captures a radiation image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiation image in a phosphor and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor. The radiation film with the recorded radiation image is supplied to a developing device to develop the radiation, or the stimulable phosphor panel is supplied to a reading device to read the radiation image as a visible image.
In the operating room or the like, it is necessary to read and display a recorded radiation image immediately from a radiation conversion panel after the radiation image is captured for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting a radiation directly into an electric signal or converting a radiation into visible light with a scintillator and then converting the visible light into an electric signal to read a detected radiation image.
Radiation image capturing systems incorporating such a radiation conversion panel manage an exposed radiation dose that is applied to a subject in order to prevent the subject from being irradiated with an excessive amount of radiation.
For example, Japanese Laid-Open Patent Publication No. 2007-097909 discloses an exposed radiation dose managing system including an image management server for calculating and accumulating an exposed radiation dose from information about radiation images of a subject and confirming the accumulated exposed radiation dose applied to the subject to prevent the subject from being irradiated with an excessive amount of radiation.
Japanese Laid-Open Patent Publication No. 6-142089 discloses an X-ray managing apparatus for determining an accumulated value representing the sum of an X-ray dose applied to a subject in the past and a predicted value of X-ray dose before the subject is irradiated with X-rays, and making an advance warning, when necessary, based on the accumulated value.
Japanese Laid-Open Patent Publication No. 2004-201757 reveals an X-ray diagnosing system which allows the accumulated exposed radiation dose of a subject to be shared by different hospital facilities.
The systems and apparatus disclosed in all the documents referred to above, manage an exposed radiation dose applied to a subject, but not a radiation dose applied to a radiation conversion panel. Since the radiation conversion panel has its sensitivity variable when irradiated with a radiation, the radiation conversion panel may fail to produce an appropriate radiation image depending on the accumulated exposed radiation dose applied thereto.